Download the new rpm packages from the CentOS website for openssl and openssl-devel.
Copy these onto the offline system that needs to be upgraded.
Make a new folder that will be set this up as a repository. I used /home/user/repo
make a new repository file under /etc/yum.repos.d/
[centoslocal] name=CentOS Local baseurl=file:///home/user/repo enabled=1 gpgcheck=0
Save this as /etc/yum.repos.d/centoslocal.repo
copy the new rpm files into /home/user/repo
In the /home/user/repo directory run:
Updating yum now should detect the new repo and realize that there is an update for the openssl packages. Accept the changes and they should be applied automatically and successfully.